Number system:

We all know that computer is an electronic device and it accepts and stores data in the form of digits, numbers, letters, special characters, etc.
But while processing, the data is converted into computerís own language, i.e., machine language, which is in the form of Binary Digits-0 and 1. These binary digits are used to represent the absence and presence of an electronic pulse. For example, 0 represents the absence (OFF) of electronic pulse and 1 presence (ON) of electronic pulse.
As computer works on binary numbers, the number system is used for representing these electronic pulses.





Generally a computer deals with the following system:
  • Decimal number system
  • Binary number system
  • Octal number system
  • Hexadecimal number system

Decimal number system:
The decimal number system is the base 10 number system. It includes all the digits from 0 to 9 (0, 1, 2, 3, 4, 5, 6, 7, 8 and 9). Decimal number system is the most commonly used number system. Decimal numbers do not necessarily contain a decimal point. For example, 563, 56.3 and 563 are all decimal numbers.
In decimal number system, successive positions to the left of the decimal point represent units, tens, hundreds; thousands, etc. however, notice that each position represents a specific power of the base (10).

For example, decimal number 567(written as 567₁₀) consists of digits of digit 7 in unitís position, 6 in tens positions and 5 in hundreds positions and its value can be written as:

(5* 10≤) + (6 * 10Ļ) + (7 * 10⁰)
= 500+60+7
= 567